This invention concerns a lubricating oil system for an engine, and more particularly relates to a system for maintaining proper oil quality in an internal combustion engine.
In conventional piston driven four-cycle internal combustion engines powered by gasoline, particularly those engines utilized in automotive vehicles, a crankcase is provided as a reservoir for a lubricating oil which is distributed to moving components susceptible to frictional wear. In the course of extended use, however, the oil loses its initial qualities due to :(a) accumulation of combustion-generated solid debris and acidic chemical species, (b) accumulation of frictionally generated metallic particles, and (c) thermally induced degradation of molecular weight with attendant drop in viscosity. Such deterioration in the quality of the lubricating oil is generally remedied by periodically draining all the oil from the crankcase after a prescribed length of usage and replacing it with fresh oil.
Such periodically complete oil changes, however, are sometimes not carried out when required due to neglect or oversight, thereby resulting in damage to the engine.
In the case of diesel engines, systems have been disclosed for gradually and continuously removing old oil by feeding it into the fuel, and replenishing fresh oil to the oil reservoir. Although such expendient may be successful in a diesel engine, it cannot be done with a gasoline engine. Furthermore, such method of discarding old oil produces a significantly dirtier exhaust gas of air-polluting consequences. In those systems disclosed for automatically removing oil from a crankcase, or adding oil to a crankcase, very specialized and expensive components are utilized which can only be incorporated into the engine by the manufacturer.
It is accordingly an object of the present invention to provide a system for partially exchanging old oil for fresh oil in a crankcase at periodic intervals.
It is another object of this invention to provide a system as in the foregoing object wherein the rate at which the oil is partially exchanged is substantially equal to the prescribed rate for a complete oil change.
It is a further object of the present invention to accomplish the aforesaid partial exchange of oil utilizing means for recording the extent of use of said oil and dictating automatic or manual activation of oil changing means.
It is yet another object of this invention to provide apparatus for achieving the aforesaid oil changing which can be installed into an existing internal combustion engine.
These objects and other objects and advantages of the invention will be apparent from the following description.